Most dental patients have suffered from the gag reflex when X-ray films or mold plaster is placed in the back of their mouth. As most victims know, the impulse to gag is uncontrollable and makes some dental procedures intolerable. This stimulation of the gag reflex can be a stressful time for the patient and the dentist. It can lead to delay of treatment where, for example, the patient is not able to complete X-ray or crown fitting procedures. The fear of discomfort and embarrassment from the gag reflex keeps many patients from receiving regular dental care. Still other patients are not even able to adequately perform proper oral hygiene due to gagging, even during tooth brushing.
The gag reflex starts with a noxious stimulation of the oropharynx, or back of the mouth. This palatal stimulation in turn activates the cranial Nerves V, IX, and X, causing the brain to send the gag reflex to the back of the throat. The gag reflex protects the airway and triggers the contraction of the superior laryngeal muscles.
Bertolucci, Nausea Control Device, U.S. Pat. No. 4,981,146, Jan. 1, 1991, describes a nausea control device in the form of a watch-like housing attachable to the human wrist by an adjustable attachment band. The device uses non-invasive nerve stimulation whereby electricity is passed through two electrodes to stimulate nerves located on the ventral side of the wrist (this anatomical position is sometimes referred to as the palmar side of the wrist). The treatment provided by the device is sometimes referred to as electro-acupuncture, which is a form of acupuncture, and the ventral site of application is referred to in the acupuncture art as the P6 point, pericardium 6 point, or master point of the pericardium meridian (sometimes referred to as the vascular meridian). A primary object of the invention is to provide a non-chemical, non-invasive, painless and inexpensive method of alleviating nausea. It is also portable, self-contained and convenient to the patient. Electrical pulse repetition rate of approximately 70 pulses per second and a pulse width of 80 microseconds has been found to provide effective relief of nausea in a patient. Our currently preferred electrical pulse pattern comprises about 350 microsecond pulse width at about 31 pulses per second at power levels of about 10-35 milli-amps peak pulse height. Thus a wide range of pulse patterns may be used in non-invasive nerve stimulation devices.
Sanders, Device for Controlling the Glottic Opening, U.S. Pat. No. 4,907,602, Mar. 13, 1990, describes a method of controlling the movement of the vocal cords in order to open and close the airway passage in a human subject. The method employs transcutaneous (passing or entering through the skin) or transmucosal electrical stimulation of the recurrent laryngeal nerve (RLN), which is delivered by applying electric charge from an electrode in the form of a probe or an indwelling device, to the intact neck skin at specific points along the tracheoesophageal groove or to mucosa within the esophagus, larynx, or trachea. The resulting vocal cord excursion is related to frequency of the electrical stimulus.
Where Sanders, Device for Controlling the Glottic Opening, U.S. Pat. No. 4,907,602, Mar. 13, 1990 teaches direct electrical stimulation to the nerves in the area to be affected, in that case the neck to control movement of the vocal cords, Bertolucci, Nausea Control Device, U.S. Pat. No. 4,981,146, Jan. 1, 1991, teaches indirect electrical stimulation to the nerves in the area to be affected, in that case the wrist to control nausea.